Indonesia intensifies aerial firefighting as peatland fires blanket Borneo and haze spreads into Malaysia

Indonesia has intensified ground and aerial firefighting operations across Borneo and Sumatra, deploying thousands of personnel and dozens of water-bombing aircraft against forest and peatland fires that have blanketed cities in choking smoke and sent haze drifting across the border into Malaysia and Brunei. The fires, concentrated in the provinces of West, Central and South Kalimantan and in Riau, South Sumatra and Jambi, have intensified through August as Indonesia enters what its disaster agency calls the most dangerous stretch of the annual dry season.

In West Kalimantan's provincial capital, Pontianak, authorities have suspended in-person classes indefinitely and shifted lessons online because of hazardous air quality, a step mirrored by nearly 600 schools in Malaysia's Sarawak state, affecting roughly 200,000 students. The smoke has been visible from satellite imagery for days, and by Monday it had pushed air-pollution readings in parts of Sarawak close to the threshold Malaysian authorities classify as "very unhealthy."

The scale of the fires

Indonesia's forestry ministry said its joint fire-control operation in Kalimantan has now run for 48 consecutive days and involves 12,880 personnel drawn from the Manggala Agni forest fire brigade, the military, police, regional disaster agencies and volunteer groups. According to the ministry's provisional figures, fires have burned across roughly 38,300 hectares in West Kalimantan, 8,000 hectares in South Kalimantan, 7,600 hectares in Central Kalimantan, 2,700 hectares in East Kalimantan and 400 hectares in North Kalimantan.

Nationally, government figures cited by wire reporting put the area burned since the start of the current wave at more than 36,000 hectares across ten provinces, with the heaviest hotspot activity detected in South Sumatra, West Kalimantan and Central Kalimantan. Indonesian police have arrested 72 people suspected of deliberately starting fires and are investigating four companies accused of using fire to clear land cheaply ahead of planting season. More than 24,000 ground firefighters have been mobilized nationwide, backed by roughly 30 water-bombing aircraft and helicopters over Kalimantan and 22 more over Sumatra, along with 45 weather-modification flights that have seeded clouds with 45 tons of material in an effort to induce rain over the driest areas. Separately, satellite monitoring compiled by researchers shows nearly 124,000 hectares burned nationwide in July alone, before the current spike, underscoring how much of this year's damage predates the current emergency response.

A worsening, recurring crisis

Indonesia's peatlands, drained and deforested over decades for palm oil and pulpwood plantations, burn easily once dried out and release smoke that lingers for weeks because the fires smolder underground in carbon-rich soil rather than burning out quickly like surface vegetation fires. The country has suffered severe transboundary haze episodes roughly every few years since a catastrophic outbreak in 1997, with further major crises in 2015 and 2019 that closed airports, schools and border crossings across the region and, in 2015, were estimated to have caused billions of dollars in economic losses across Southeast Asia.

This year's conditions have been aggravated by the return of an El Nino weather pattern, officially declared in June, which is suppressing rainfall across the archipelago and is forecast to strengthen further into October. The Singapore Institute of International Affairs' annual Haze Outlook report assigned 2026 a "red," or high-risk, rating for a severe transboundary haze event — only the second time the institute has issued that top rating since it began publishing the assessment in 2019. Under the region's coordinating framework, the ASEAN Agreement on Transboundary Haze Pollution, member states activated a heightened alert level this month requiring Indonesia, Malaysia, Brunei, Singapore, Thailand and Timor-Leste to file daily reports on fire and haze conditions.

Schools closed, wildlife habitat threatened

Beyond the school closures in Pontianak and Sarawak, conservationists have warned that fires are creeping toward habitat relied on by some of Borneo's remaining wild orangutan populations, including forest near a rehabilitation center in West Kalimantan that houses more than 60 rescued animals, as well as peat forest in Ketapang district thought to support up to 1,750 wild orangutans. Health authorities in affected provinces have urged residents, particularly children, the elderly and people with respiratory conditions, to limit outdoor activity as air-pollution readings climb into unhealthy ranges. In Malaysia, the timing has raised particular concern because the haze coincides with preparations for the country's National Day celebrations on August 31 and Malaysia Day festivities in Kuching, Sarawak, on September 16, both of which draw large outdoor crowds.

'We've already agreed to increase our collaboration'

Officials on both sides of the border have described the response as a joint effort even as they acknowledge the scale of the problem. Indonesia's forestry minister, Raja Juli Antoni, said the deployment followed a direct instruction from President Prabowo Subianto, telling reporters the government's approach was to ensure "the state is present to prevent forest fires" and that additional budget would be released if current resources proved insufficient. Malaysia's Natural Resources and Environmental Sustainability Minister, Arthur Joseph Kurup, said Jakarta had agreed this week to let Malaysian cloud-seeding aircraft operate in Indonesian airspace along their shared border in Borneo, and described broader coordination between the two governments on monitoring and enforcement.

"I met up with all my counterparts, for example the Minister of Environment in Indonesia, and we've already agreed to increase our collaboration. Collaboration in terms of monitoring hotspots, more enforcement agencies to make sure there's no open burning. We can also share our airspace in case we need to do any cloud seeding operations, maybe share our assets too," Kurup told reporters.

Malaysia's Department of Environment has continued to issue daily air-quality bulletins as readings in Sarawak fluctuate between moderate and unhealthy, while Malaysia's environment ministry, the Ministry of Natural Resources and Environmental Sustainability, said it was prepared to bring the matter to the national cabinet if conditions worsened around the upcoming holiday. Regional monitoring groups have separately renewed calls for stronger enforcement of the ban on land-clearing by fire, noting that repeated haze episodes have followed a similar pattern of drought, budget shortfalls and delayed enforcement in previous El Nino years.

What happens next

Indonesian officials say the firefighting and cloud-seeding operations will continue through the remainder of the dry season, which authorities expect to persist into October as El Nino strengthens. Provincial governments in Central Java and East Java have separately declared emergency drought and fire alert status running into the final months of the year, and Central Kalimantan's disaster agency has said it is weighing whether to escalate its own designation from alert to full emergency status as hotspot counts continue to climb. Whether the cross-border cooperation announced this week — including shared airspace for cloud seeding and stepped-up hotspot monitoring — meaningfully reduces the haze reaching Malaysia and Brunei is likely to become clearer only once the two national holidays at the end of this month and in mid-September have passed, giving both governments a near-term test of the new arrangement.